The present invention is directed toward a safety apparatus and more particularly toward a safety apparatus in the form of a load attachment system such as commonly used as a horizontal lifeline. The invention includes a load attachment traversing device that engages the lifeline for movement therealong and which can traverse intermediate supports without detachment from the line.
Horizontal lifelines have been employed for many years to provide fall protection for workers on elevated structures. In fact, such horizontal lifelines are required and have been mandated by safety rules and regulations in many jurisdictions. Such lifelines normally consist of a rope or cable suspended between two structures such as the vertical beams of a building or the like which may be 10, 20 or even 100 feet apart. A safety harness or safety belt is worn by a worker and a lanyard connected to the harness or belt attaches to the horizontal lifeline or cable. The end of the lanyard may include either a loop which can freely move along the length of the lifeline or it may include a grooved roller in the form of a pulley or the like that rolls along the line. This allows the worker to move freely along the length of the lifeline to accomplish his intended tasks. In the event that the worker losses his footing or otherwise falls, the horizontal lifeline, through the lanyard and harness or safety belt will arrest the fall and prevent the worker from suffering injury. The use of such a lifeline is described, for example, in U.S. Pat. Nos. 5,332,071; 5,458,214 and 5,598,900.
In order to function properly, the horizontal lifeline must be sufficiently taught so that the worker""s lanyard can easily move across the same and so that the lifeline can function as a steadying rail for the worker, if necessary. However, when the lifeline is sufficiently taught so that the same assumes a linear or substantial linear configuration, the resistance force magnitude required to effectively withstand the load impact of a falling worker becomes theoretically exceedingly large. In the event of a fall, the construction worker ordinarily generates many times his weight in the impact force exerted by the lanyard against the cable or lifeline. Thus, the tension in the lifeline is critical since this determines the amount of sag in a lifeline which, in turn, determines the load amplification by which a vertical fall arrest force applied to the lifeline is multiplied by. Therefore, it is important to know the amount of tension applied to a lifeline. In fact, the amount of tension is frequently dictated by safety rules or regulations in many jurisdictions.
A winch or similar type device is frequently used to tension a horizontal lifeline when the same is in use. The lifeline is normally connected to one anchoring point and then passes through the winch. The winch, in turn, is connected through an anchoring line to the second anchor point. A winch-like device for tightening a horizontal lifeline is described, for example in U.S. Pat. No. 5,957,432 issued to the present applicant, the subject matter of which is incorporated by reference herein.
On short runs of 10 or 20 feet or so, the horizontal lifeline is normally supported only at the ends thereof. With substantially longer runs, however, it frequently becomes necessary to provide intermediate supports to prevent the line from sagging. This creates problems when a worker is attempting to move along the length of the line as the intermediate supports will prevent the loop or pulley at the end of his lanyard from passing. Thus, it would become necessary for the worker to detach his lanyard, move the same to the other side of the intermediate support and then reattach it again. This obviously creates a significant safety hazard.
Devices have been available and proposed in the past which are capable of traversing the intermediate supports. One such device, sold under the name Transfastener by Hy-Safe Technology, of Silver Lake, Wis., is produced by Latchways Ltd., of Wiltshire, England. Similar devices are shown, for example, in U.S. Pat. Nos. 1,122,024; 1,429,007; 4,265,179; 4,462,316 and 4,470,354.
Each of these devices is comprised essentially of an upper portion and a lower portion where one of them is essentially in the form of a rotatable star wheel or the like and the other includes a track adapted to cooperate with the ends of the star wheel. As the device moves along a line, the star wheel is caused to rotate when it engages an intermediate support and the ends of the star wheel roll or slide across a track on the second portion of the device. It is, therefore, the interaction between the ends of the star wheel and the track on the second member which must support the weight should a worker fall or in the event that loads are being transported by the device. This can create excessive wear and ultimately possible failure which could create a safety hazard. In addition, because of the tolerances that are required in ensuring that the ends of the star wheel properly meet with the second portion of the device, these products can be expensive to produce and maintain.
The present invention is designed to overcome the deficiencies of the prior art discussed above. According to the invention, a load attachment system such as commonly used as a horizontal lifeline safety system includes a substantially horizontal lifeline secured at its ends to a building structure and supported intermittently along its length by intermediate supports. Each support includes a horizontal bar and a partial vertical bar. The system further includes a load attachment device having a pair of grooved rollers that rides on the lifeline. A load is supported from the bottom of a C-shaped member which has its top connected to the rollers thereby allowing the device to traverse the supports. The bottom of the C-shaped member also carries a rotatable paddle wheel which prevents the device from being removed from the line. The paddle wheel rotates when a paddle is engaged by the support""s horizontal bar as the device traverses the support.
In a second embodiment of the invention, each of the intermediate supports includes a pair of horizontal bars. A short length of a hollow metal retaining tube is secured to the free ends of the horizontal bars in alignment with the horizontal lifeline which passes therethrough. The grooved wheels of the load attachment device ride on the lifeline as in the first embodiment and ride on the upper surface of the retaining tube.